1. Field of the Invention
The present invention relates to a method of manufacturing a solar battery, and more particularly to a method of manufacturing a solar battery which is suitable for sequentially and serially connecting a plurality of solar battery elements by joining a light receiving surface of one solar battery element to a back surface of the next solar battery element by an electrically conductive member.
2. Description of the Prior Art
In the prior art, a method of serially connecting a plurality of solar battery elements is illustrated in FIGS. 1A and 1B. In this method as shown in FIGS. 1A and 1B, the front and back surfaces of each solar battery element 10a, 11b are provided with a eutectic solder deposition layer, or a preliminary eutectic solder layer formed by deposition, or a paste solder layer formed by printing or the like. A conductor lead 16 of an electrically conductive member having a eutectic solder deposition layer or the like formed on the surface beforehand and bent stepwisely at the center thereof is disposed to bridge the light receiving surface 12 of a solar battery element 10a and the back surface 14 of another solar battery element 10b. Then, in a furnace of the resistance heating type and in an atmosphere of H.sub.2, N.sub.2, Ar gas or the like, an electrode pattern 18 of the solar battery element 10a and the conductor lead 16 are welded to each other, and the conductor lead 16 and an electrode pattern 20 of the solar battery element 10b are also welded and thus the connection of the solar battery elements 10a and 10b is completed. In this method, it takes several seconds to several tens of minutes to melt the solder (melting point above 183.degree. C.) contained in the solder deposition layer or the like formed on the surface of the conductor lead 16. Further, since the conductor lead 16 is a single integral member of stepwisely bent structure, automatic feeding of the conductor lead 16 is difficult and thus this method was not suitable for mass production. Furthermore, since the material of the conductor lead 16 is a Fe-Ni alloy (Fe-42Ni), although the thermal expansion coefficient is small, the rigidity is high, and thus there was a problem in that the stress of the conductor lead 16 imparted to the electrode pattern 18 of the light receiving surface 12 after the connection was large and peelings and cracks were caused.
In addition, for the furnace of the resistance heating type used with an atmosphere of H.sub.2, N.sub.2, Ar gas or the like, a large conveyer furnace is required and hence there was a disadvantage that energy consumption including gas, electric power and the like was large.
Another method of connecting the solar battery elements has been proposed as illustrated in FIG. 2. In this method, solar battery elements 10a and 10b are disposed respectively on corresponding conductors 24 located on a substrate 22, and then a film 28 formed with a conductive pattern 26 of copper foil having solder deposited thereon is placed on the solar battery elements 10a and 10b such that the conductive pattern 26 is in contact with the conductor 24 and with the electrode pattern 30. Then heat and pressure are applied to these portions in contact with each other to effect welding.
However, in this method, the heat capacity of the substrate 22 is large, and since a considerable time is needed for the solder to become melted and solidified, it was difficult to serially connect the solar battery elements at high speeds.